Oil-gas treatment system, oil-gas treatment method and mechanical apparatus

An oil-gas treatment system comprising:

• an oil-gas separation device configured to perform an oil-gas separation treatment on oil-gas generated by an oil-gas generation device, wherein the oil-gas separation device comprises:
• a lubrication oil box for containing lubrication oil;
• and
• a plurality of sub oil-gas separation devices cascade-connected in stages, each stage being configured to perform the oil-gas separation treatment on the oil-gas, and the lubrication oil box serving as one of the plurality of sub oil-gas separation devices;
• a first oil-gas delivery device which is communicated with the lubrication oil box and is configured to convey at least a part of the oil-gas into the lubrication oil box, wherein the lubrication oil box is configured to separate the oil-gas conveyed into the lubrication oil box, and a separated oil product is left in the lubrication oil box,
• a gas discharge pipe in communication with a last stage of the plurality of sub oil-gas separation devices and with a discharging environment;
• an oil mass detector configured to detect an oil content in the gas discharge pipe;
• a valve inside the gas discharge pipe;
• an oil-gas return pipe between the last stage and at least another stage of the plurality of sub oil-gas separation devices;
• and
• a controller configured to control the valve to be opened for discharging a gas product in the last stage of the plurality of sub oil-gas separation devices into the discharging environment when the oil content is no greater than a standard value, and to control the valve to close the gas discharge pipe to the discharging environment, when the oil content is greater than the standard value, so as to facilitate a return of the gas product in the last stage to the at least another stage of the plurality of sub oil-gas separation devices through the oil-gas return pipe for additional oil-gas separation treatment.